One-Dish Salmon - cooking recipe

Ingredients

3 tablespoons olive oil
1 large onion, sliced
2 salmon fillets
1 (14 1/2 ounce) can diced tomatoes, drained (I used fire-roasted, but would be good with spicy tomatoes)
1/2 cup mayonnaise
2 cups fresh spinach leaves

Preparation

Heat olive oil in skillet. Saute onion in oil until almost tender.
Mix mayonnaise and tomatoes in bowl. Coat salmon with mixture.
Push onions to side of skillet, place salmon fillets in pan. Pour rest of mayo-tomato mixture in also. Cook 3-4 minutes on each side.
Add the spinach leaves in the last 2 minutes of cooking. Cover to let spinach steam.